See also

On Unix systems with POSIX threads support, Apache httpd can
now run in a hybrid multiprocess, multithreaded mode. This
improves scalability for many, but not all configurations.

New Build System

The build system has been rewritten from scratch to be
based on autoconf and libtool.
This makes Apache httpd's configuration system more similar to
that of other packages.

Multiprotocol Support

Apache HTTP Server now has some of the infrastructure in place to
support serving multiple protocols. mod_echo has
been written as an example.

Better support for non-Unix
platforms

Apache HTTP Server 2.0 is faster and more stable on non-Unix
platforms such as BeOS, OS/2, and Windows. With the
introduction of platform-specific multi-processing modules (MPMs) and the
Apache Portable Runtime (APR), these platforms are now
implemented in their native API, avoiding the often buggy and
poorly performing POSIX-emulation layers.

New Apache httpd API

The API for modules has changed significantly for 2.0.
Many of the module-ordering/-priority problems from 1.3 should
be gone. 2.0 does much of this automatically, and module ordering
is now done per-hook to allow more flexibility. Also, new calls
have been added that provide additional module capabilities
without patching the core Apache HTTP Server.

Apache httpd modules may now be written as filters which act on
the stream of content as it is delivered to or from the
server. This allows, for example, the output of CGI scripts to
be parsed for Server Side Include directives using the
INCLUDES filter in mod_include. The
module mod_ext_filter allows external programs to
act as filters in much the same way that CGI programs can act as
handlers.

Multilanguage Error Responses

Error response messages to the browser are now provided in
several languages, using SSI documents. They may be customized
by the administrator to achieve a consistent look and feel.

Simplified configuration

Many confusing directives have been simplified. The often
confusing Port and BindAddress directives
are gone; only the Listen
directive is used for IP address binding; the ServerName directive specifies the
server name and port number only for redirection and vhost
recognition.

Native Windows NT Unicode Support

Apache httpd 2.0 on Windows NT now uses utf-8 for all filename
encodings. These directly translate to the underlying Unicode
file system, providing multilanguage support for all Windows
NT-based installations, including Windows 2000 and Windows XP.
This support does not extend to Windows 95, 98 or ME, which
continue to use the machine's local codepage for filesystem
access.

New module in Apache httpd 2.0. This module allows supporting
browsers to request that content be compressed before delivery,
saving network bandwidth.

mod_auth_ldap

New module in Apache httpd 2.0.41. This module allows an LDAP
database to be used to store credentials for HTTP Basic
Authentication. A companion module, mod_ldap
provides connection pooling and results caching.

The proxy module has been completely rewritten to take
advantage of the new filter infrastructure and to implement a
more reliable, HTTP/1.1 compliant proxy. In addition, new
<Proxy>
configuration sections provide more readable (and internally
faster) control of proxied sites; overloaded <Directory
"proxy:..."> configuration are not supported. The module
is now divided into specific protocol support modules including
proxy_connect, proxy_ftp and
proxy_http.

A new ForceLanguagePriority directive can be used to assure that
the client receives a single document in all cases, rather than
NOT ACCEPTABLE or MULTIPLE CHOICES responses. In addition, the
negotiation and MultiViews algorithms have been cleaned up to
provide more consistent results and a new form of type map that
can include document content is provided.

Autoindex'ed directory listings can now be configured to
use HTML tables for cleaner formatting, and allow finer-grained
control of sorting, including version-sorting, and wildcard
filtering of the directory listing.

New directives allow the default start and end tags for SSI elements
to be changed and allow for error and time format configuration
to take place in the main configuration file rather than in the
SSI document. Results from regular expression parsing and grouping
(now based on Perl's regular expression syntax) can be retrieved
using mod_include's variables $0
.. $9.

mod_auth_dbm

Now supports multiple types of DBM-like databases using the
AuthDBMType directive.

Notice:This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.